[Jemma]

I just looked all over the internet and there are stories about those little black worms. They are indeed flea larvae, tiny small black, moving. Which means the puppy is truly infected. Be careful of eyes but give the dog a bath in Dawn dish detergent. Leave on a few minutes and make sure you rinse rinse rinse. Make sure you use Dawn, nothing else right now.
Now that's the easy part. Will they come back? Yes because you now have fleas throughout your house laying flea larvae. Bedding needs to be washed. And you and pooch need to bomb the house and get out for a few hours. I would pick a day where you can both wash the dog and get out of the house when you bomb. To wash the pooch and wait a week before flea bombing would be senseless as it gives time for the fleas to jump right back on the dog. Also bring stool sample to vet. As a result of all the flea bites and larvae, she may now have worms. Yup fleas can transmit this.
Good luck, a lot of work needs to be done. Also check the ears for mites as well.
Hope this helps.